Devices may be used for example in the form of tanks or tank systems of motor vehicles in order to prevent overfilling of individual pressure accumulator vessels with fuel during a refueling or filling process. After the filling process, the fuel must be withdrawn again in order to be consumed. Various arrangements of pressure accumulator vessels and valves, and methods for the operation thereof, are known for this purpose.
Specifically, in the case of motor vehicles that are operated with natural gas or hydrogen, a large travelling range is desired on the one hand, but on the other hand, there may me often only limited space available for the installation of the pressure accumulator vessels, such that it may me often advantageous for multiple pressure accumulator vessels of different capacity to be accommodated at different locations in the vehicle. It is also true, however, in the case of static plants, in particular in the case of working machines, that a long service life may me desired but there may me often only limited space available.
German Patent Publication No. DE 10 2009 049687 A1 discloses a gas vessel arrangement for a gas engine having multiple gas vessels, and a method for the operation of a gas vessel arrangement of the type. The gas vessel arrangement for a gas engine has multiple gas vessels, wherein each of the multiple gas vessels may me assigned in each case at least one valve device; a common gas line which may me connected at one side to the multiple gas vessels and at the other side to a filler neck and to the gas engine, and a control device for the actuation of the valve devices of the multiple gas vessels. The gas vessels may optionally have identical or different volumes. The purported advantages of the arrangement and operating method, however, come to bear in particular in the case of different gas vessel volumes or asymmetrical arrangements of the gas vessels and of the gas lines.
The gas vessel arrangement of DE 10 2009 049687 A1 is characterized in that a control device is designed to at least temporarily actuate the valve devices of the multiple gas vessels such that a first gas vessel and a second gas vessel are connected to one another such that gas can flow between the first and the second gas vessel for the purposes of pressure equalization. In the method, likewise described in DE 10 2009 049687 A1, for operating a gas vessel arrangement for a gas engine having multiple gas vessels, a highly compressed gas is delivered from at least one storage tank simultaneously into the multiple gas vessels. During a refueling process of the gas vessel arrangement, the valve devices of a first gas vessel and of a second gas vessel are at least temporarily opened in order to connect the first and the second gas vessel to one another such that gas can flow between the first and the second gas vessel for the purposes of pressure equalization.
The two gas vessels are connected via a common gas line both to the gas engine and also to a filler neck. The latter can be connected via a corresponding fuelling hose in order for the gas vessels of the gas vessel arrangement to be filled with a highly compressed gas, for example natural gas from one or more storage vessels of a natural gas refueling facility. The filler neck is equipped with a tank flap switch that detects an opening and closing of the tank flap of the filler neck. The tank flap switch may optionally also be designed to detect the presence of a fuelling nozzle in the open filler neck, and an electronic bus connection via the filler hose permits communication between the filling station and a control device in the vehicle.
DE 10 2009 049687 A1 is one representative of a number of known systems of combined pressure accumulator vessels and valve arrangements which make it possible for pressure accumulator systems to be filled with fluids and for the fluids to be withdrawn from the pressure accumulator systems. Furthermore, numerous further technical facilities are known which enable a fill pressure of an individual pressure accumulator vessel or of an entire pressure accumulator system to be monitored and limited through measurement of the pressure and through electronic control of electromagnetic valves.
In the applications mentioned, it may me desirable for an admissible operating pressure of a pressure accumulator vessel or of a pressure accumulator system to be reliably adhered to during the course of a filling process, and thus for maximum operational safety to be ensured. It should be possible for the filling process to be performed as quickly as possible and with only low energy losses. Wear on valve components should be kept low, and damage to pressure accumulator vessels and pressure lines should be prevented. Furthermore, it may me desirable for the piping of the pressure accumulator systems to be simplified, and for the number and complexity of the pressure lines to be reduced.
Pressure accumulator vessels for mobile applications are adapted in terms of design, and constructed, for the corresponding pressure level depending on the type of application. This gives rise to accumulators which, with regard to their strength, correspond to the operating pressure and satisfy the ECE guidelines and which, in the case of high-pressure systems, for example, above 200 bar, take up a corresponding amount of space. Small pressure accumulator vessels with the same admissible operating pressure in each case, or modularly assembled component pressure accumulators with equal admissible operating pressure, are thus of relatively very large construction and relatively expensive, and therefore have not hitherto become established. Furthermore, in conventional systems and methods, there is no adequately reliable technical solution that permits the simultaneous filling of pressure accumulator vessels with different admissible operating pressures from the same tank neck.
In accordance with the presently applicable legal regulations, all pressure accumulator vessels of a system must be configured to have an identical admissible operating pressure (maximum operating pressure). It is presently also prohibited to refuel at filling stations whose filling pressure (fuelling pressure) exceeds the maximum working pressure of the pressure accumulator vessels installed in a motor vehicle.